Figure 1 below shows the cross section of a retaining wall.
Weight of Wedge ABC
From Triangle ABC,
Area of Triangle ABC =
From the sine rule,
Substituting the value of W from the equation (3.34) into (3.35) we get,
In order to get the maximum value of Pp,
When, (leveled backfilled), (no wall friction) and (vertical interface between wall and backfill), then, . The point of application of Pp is at a distance of H/3 above the base of the wall.